Conventional threaded light bulb sockets for incandescent bulbs are notorious for difficult removal of the bulbs when over time a bulb may become jammed in the socket. A light bulb may therefore break from the threaded base and present a electrical shock hazard to a user of the socket. Removal of the bulb from the socket after the threaded base has broken from the glass globe can be dangerous if not annoying and problematic.
Also, it is not always easy or convenient to maintain bulbs in threaded light bulb sockets. Hard to reach threaded sockets in high ceilings do not lend themselves to turning from below. Large arrays of sockets present a serious cumulative time expenditure for unthreading and threading each one even if every socket is easily accessed.
Threaded sockets and bulbs have been tolerated over the years because they make dependable and predictable electrical connections. However, there is a long felt need for a quicker, easier and safer way of connecting light bulbs to a power supply.